Hitherto, a two-piece type automobile wheel including a wheel disc and a wheel rim is integrally formed in such a manner that an outer peripheral surface of a disc flange portion formed on an outer periphery of the wheel disc is fitted and welded on an inner peripheral surface of the wheel rim. As the above-mentioned automobile wheel, as proposed in, for example, Patent Literature 1, there has been known an automobile wheel having a plurality of spokes formed in the wheel disc. In the wheel disc of the automobile wheel, the plurality of spoke portions are extended equiangularly to a wheel radially outer side from an outer peripheral edge of a hub mounting portion to be coupled to a hub of an axle, and the plurality of spoke portions couple the hub mounting portion and the disc flange portion together. With this configuration, in the wheel disc, there are formed substantially triangular openings (ornamental holes) each being surrounded by the adjacent spoke portions, the disc flange portion, and the hub mounting portion.
In the automobile wheel proposed in Patent Literature 1, side edge portions formed on both sides of each of the spoke portions in a widthwise direction are bent into an L-shape in cross-section. Further, a coupling portion for continuously coupling the side edge portions of the adjacent spoke portions is formed on an outer periphery of the hub mounting portion.
Further, the disc flange portion of the wheel disc includes an annular fitting portion to be fitted on an inner peripheral surface of a well portion of the wheel rim, and circular-arc plate portions each having a predetermined width and being extended from the fitting portion at a position between the adjacent spoke portions so as to be bent to a wheel radially inner side. Each of the circular-arc plate portions is formed so as to be dented to a back side with respect to an outer end of the side edge portion formed on each side of the spoke portion, and is integrally coupled to the outer end of the side edge portion in a stepped manner.